Synthesis and photoluminescence properties of Eu3+-activated LiCa3ZnV3O12white-emitting phosphors

Single-component white-emitting phosphors are highly promising for applications in phosphor-converted white light-emitting diodes. In this paper, novel single-phase LiCa3(1-x)ZnV3O12:Eu3+ (x = 0-0.05) phosphors with tunable white emissions were prepared by a conventional solid-state reaction. The LiCa3ZnV3O12 (x = 0) phosphor showed an efficient self-activated bluish-green emission due to the V5+-O2- charge transfer transition of the [VO4]3- groups, and possessed an intense broad excitation spectrum in the 250-400 nm wavelength range. Together with the [VO4]3- emission, the red emission of Eu3+ ions was also observed in LiCa3(1-x)ZnV3O12:Eu3+ phosphors. The energy transfer from the [VO4]3- groups to the Eu3+ ions was studied. Importantly, the emission colors of LiCa3(1-x)ZnV3O12:Eu3+ phosphors varied from greenish-blue to whitish and then to red with increasing Eu3+ content and the white-light emission was realized in the single-phase phosphor of LiCa3ZnV3O12:0.003Eu3+ by combining the [VO4]3--emission and the Eu3+-emission. The energy-transfer efficiency from [VO4]3- groups to Eu3+ ions in the LiCa3ZnV3O12:0.003Eu3+ sample was determined to be about 52% and the internal quantum efficiency of the LiCa3ZnV3O12:0.003Eu3+ phosphor was found to be about 41.5%. In addition, the CIE chromaticity coordinates of LiCa3ZnV3O12:0.003Eu3+ were (x = 0.3374, y = 0.3596), and the correlated color temperature was estimated to be about 5311 K.